This invention relates to electrical surge arresters, such as lightning arresters, for protection of electrical equipment.
Arresters of substantial voltage rating, such as up to hundreds of kilowatts, normally require a plurality of electrical valve blocks and spark gaps in an electrical path whose arrangement is influenced by a number of electrical, mechanical, and economic design considerations. It has been previously recognized that the elements in the electrical path are preferably not arranged in a single linear string but rather are in a staggered stack. This results in the advantage of compactness while avoiding close proximity of elements between which undesired arcing is to be minimized. There is need however to provide adequate room to accommodate voltage grading resistor and capacitor elements and also control gap elements such as are called for by the circuit arrangements of Harder U.S. Pat. No. 3,510,726, May 5, 1970, and Osterhout U.S. Pat. No. 3,611,044, Apr. 16, 1971. A variety of such arrangements have been manufactured and used successfully. Kennon U.S. Pat. No. 3,534,221, Oct. 13, 1970, discloses examples of a prior art structural arrangement.
There remains interest in developing designs that achieve the required electrical functions while being improved with respect to ease of fabrication, economy of components, and mechanical stability in handling during fabrication, shipment, and installation. The present invention achieves improvements in those qualities.